This invention relates to a novel safety disposal syringe needle device which has medical and industrial application. More particularly, this invention pertains to a syringe which, after being used by a person to inject medication or fluid into a patient, or withdraw fluids from a patient after sampling or exposure to toxic materials, or the like, can be transformed by the person to withdraw the needle into the barrel of the syringe for disposal purposes, thereby eliminating needle stick injuries among such persons.
Needle stick injuries among medical personnel such as health care workers are of growing concern because of disease transmission, particularly the deadly virus known as HIV-1 (AIDS) and Hepatitis B. The AIDS virus for which there is no known cure is estimated to infect more than twenty million people worldwide and is spreading rapidly. Although in 1985 medical publications stated that no health care workers had become infected with the AIDS virus, it is now known that there is a significant risk to health care workers. A report in the New England Journal of Medicine, Aug. 14, 1988, indicates that the risk of acquiring HIV-1 infection is 0.35-0.74% per needle stick injury. The reported incidence of needle stick injuries to medical staff has been reported at 25.3 per 100 beds annually. In one New York hospital, at least 7% of house doctors have sustained needle stick injuries while caring for AIDS patients.
Transmission rates of Hepatitis B after needle stick exposure are much higher than that occurring with the HIV virus and may be 6-30%. The Center for Disease Control has estimated 200-300 health care workers die annually in the U.S.A. from occupationally acquired Hepatitis B.
With presently used syringes with projecting needles, potentially dangerous needle stick in juries are commonplace and most often occur between the time the medication is injected into the patient and the time the syringe is disposed of. Most injuries occur while recapping the needle or when disposing of it into a disposal container. However, maintenance personnel who handle disposed materials are also subject to needle stick injuries.
At present, there is no reason to believe that the AIDS epidemic will come to a quick end. Canada""s frequency rate at the present time is 100.2 cases per 1,000,000. The United States is a frightening 377.1 cases per 1,000,000. In Canada, according to current data projections, the incidence of AIDS rate at least doubles every eighteen months.
A number of patents disclose syringes or the like having needle protecting features. In spite of this there are no syringes which allow withdrawal and safe entrapment of needles currently on the market. This suggests difficulties with manufacture of prior patent designs. The syringe which is the subject of this patent application is manufacturable and commercially viable. In addition, after proper medical use the syringe cannot be reused and any toxic substances or infections contained within the barrel are not accessible without physical breakage of the syringe. U.S. Pat. No. 4,592,744, Jagger et al., Jun. 3, 1986, illustrates a disposable medical needle apparatus with a self-sheathing safety needle assembly. The self-sheathing safety needle has a case with a small closed end and a large open end. A needle assembly is located within the case with the needle projecting through the small closed end. A hub is connected to the needle assembly inside the case. The connector on the hub cooperates with a receiver on the small end to hold the needle assembly in the case. A flange on the hub cooperates with an inward projection in the case based from the small end to prevent movement of the needle out of the case when the needle is withdrawn from the opening in the small end. The nozzle of a syringe pushed into the hub withdraws the needle when the syringe is withdrawn. A rubber stopper on a vacuum tube withdraws the needle after the rubber stopper turns the flange to release the connector from the receiver.
U.S. Pat. No. 4,804,370, granted Feb. 14, 1989, Haber et al., discloses a disposable disease control syringe which reduces the frequency of accidental needle strikes to health care workers and prevents health-threatening reuse of the needle cannula by drug abusers. The syringe includes a cylinder having an open proximal end, a substantially closed distal end, and a retractable needle projecting through the distal end. A piston assembly having a detachable stem and a needle capturing receptacle moves axially and distally through the syringe cylinder to expulse fluid medication and to selectively engage the needle at the most distal aspect of the cylinder. The piston assembly is then withdrawn proximally through the cylinder, whereby to relocate the needle from the distal end to the proximal cylinder end. The needle capturing receptacle is locked at the proximal end of the syringe cylinder with the needle cannula retracted within and completely shielded by the cylinder. The stem is then detached from the piston assembly and discarded, thereby creating a disposal cartridge with the needle cannula rendered permanently irretrievable therewithin. Alternatively, the piston assembly can be driven distally through the cylinder for correspondingly moving the needle into contact with a puncture resistant shield located at the distal end of the cylinder, whereby the needle is axially collapsed and destroyed within the cylinder.
U.S. Pat. Nos. 4,542,749, Caselgrandi et al., and U.S. Pat. No. 3,306,290, Weltman, disclose syringes with protected needle designs.
U.S. Pat. No. 4,631,057, Mitchell, discloses a syringe which has on the body of the syringe a needle guard which can be moved from a position which shields the needle, to a retracted position which exposes the needle. U.S. Pat. No. 4,425,120, Sampson, granted Jan. 10, 1984, also discloses a shielded hypodermic syringe with a needle guard mounted on the barrel which may be extended or retracted to protect or expose the needle. U.S. Pat. No. 4,573,976, Sampson et al., also discloses a shielded needle syringe comprising a needle guard which can be retracted or extended relative to the body of the syringe, means being provided for releasably retaining the guard in the retracted position. U.S. Pat. No. 3,884,230, Wulff, granted May 20, 1975, discloses a flexible needle guard and device for a hypodermic syringe. This design appears to be directed mainly to avoiding breakage of the needle when the syringe is being used.
U.S. Pat. No. 4,258,713, Wardlaw, discloses an automatic disposable hypodermic syringe which has means for driving the hypodermic needle from a retracted position within the housing of the syringe to an injecting position whereby a portion of the needle protrudes from the housing. This device does not disclose a feature whereby the needle can be protected or retracted after use. U.S. Pat. No. 4,085,737 discloses a blood sampling syringe which includes an apparatus for protecting the open end of the needle of the syringe. The device is intended for minimizing risk of contamination of the needle tip after a blood sample has been taken. U.S. Pat. No. 4,260,543, Blum, granted May 12, 1981, discloses a hypodermic needle protection means which is designed so that the needle can be slidably moved to the interior of the needle support means upon application of pressure.
U.S. Pat. No. 4,266,544, Ward12w, granted May 12, 1981, discloses an improved disposable syringe wherein retracting means movably mounted on the housing of the syringe is adapted to pull the needle from its projecting position to a safe position whereby the needle is covered by a portion of the syringe. U.S. Pat. No. 4,139,009, Alvarez, discloses a hypodermic needle assembly with a retractable needle cover, the needle cover comprising a plurality of elastically resilient arms extending between a hub portion and a slide member, the arms acting as a restoring force for urging the slide member back over the needle forward portion when the syringe is withdrawn from contact with the skin of a patient.
U.S. Pat. No. 4,774,964 discloses a device which is designed to withdraw blood from a patient. It is not a syringe per se. It is not used for injecting fluids into a patient However, the device has the capacity to withdraw the needle into the barrel housing.
This invention relates to a safety disposable syringe. More particularly, this invention pertains to a syringe which after being used by a health care person to inject medication or fluid into a patient or withdraw fluids from a patient, can be transformed by that person to withdraw the needle into the barrel of the syringe for disposal purposes, thereby eliminating the occurrence of needle sticking injuries among such health care persons. This syringe can also be used in industrial processes for sampling or adding substances which may be toxic. After such function, the needle is withdrawn into the barrel to prevent contamination at any further point in the process or during disposal. The syringe and retractable needle feature is adapted to be used with a variety of interchangeable needles of different diameter and length utilizing a universal Luer or Luer lock coupling mechanism.
The invention pertains to a syringe comprising: (2) a hollow elongated barrel means; (b) penetration means which is adapted to removably engage with an end of the barrel means; (c) plunger means adapted to fit within and move axially in the hollow barrel means; the plunger means causing a pumping action within the interior of the barrel means between the plunger means and the end of the barrel means when the plunger means is pushed into the interior of the barrel means in the direction of the end of the barrel means; and (d) engaging means at the end of the plunger means proximate to the penetration means, the engaging means being adapted to engage the penetration means when the plunger means is fully inserted into the interior the barrel means in the direction of the end of the barrel means and cause the penetrating means to part from the barrel means and to be withdrawn into the interior of the barrel when the plunger means is withdrawn away from the end of the barrel means.
In the syringe, the penetrating means can be a hollow needle which is pointed at one end thereof, and at the end opposite to the pointed end is formed to mate with the penetration means engaging end of the barrel means. An abutting means can be positioned within the interior of the barrel means and permits the plunger to be instead into the interior of the barrel means through one end but deters the plunger means from being withdrawn from the interior of the barrel means. Alternatively, the barrel means may have two abutting means in the interior of the barrel means, the two abutting means being adapted to trap the plunger means between them when the plunger means is partially withdrawn from the barrel means.
In the syringe as defined, the engaging means may be a hook. The needle engaging means may be a female and male thread combination which is engaged by rotating the plunger relative to the barrel and penetrating means. Alternatively, the engaging means may be a cam-lack combination, the cam on the base of the needle penetrating means engaging with a receiving groove formed in the needle proximate end of the plunger, the cam-lock means engaging by rotating the plunger relative to the barrel.
In another version of the syringe, the end of the plunger proximate the penetrating means can be formed with a snap-over attachment, and the end of the penetrating means proximate the plunger can be formed with a projection which is adapted to receive and be secured by the snap-over attachment.
In a further embodiment of the syringe, the penetration means at the end proximate the plunger may be bent radially, and mate with a groove formed in the end of the plunger proximate to the bent end of the penetration means, the bent end of the penetration means and the groove in the plunger being engaged by rotating the plunger relative to the barrel of the syringe.
The needle engaging means in the syringe can be a dual female thread combination, the dual threads being formed in opposite ends of the engaging means, and a male thread means being formed on the exterior of the engaging means outside one of the female threads, the exterior male thread means being of opposite thread rotation to the dual female thread means. The end of the needle proximate to the engaging means can have a male thread removably engageable with the proximate female thread of the engaging means. The plunger proximate to the engaging means can have a male thread engageable with the female thread of the engaging means opposite to the female thread engaging the male thread of the needle means.
The invention also relates to an adapter for a syringe having a piston and a needle base fitting in the end of the syringe comprising: (a) a protrusion formed at one end of the adapter for fitting inside the hollow of a base affixed to a syringe needle; (b) releasable engagement means formed in the exterior of the adapter and being adapted to releasably engage with the interior of the needle receiving end of a syringe barrel; and (c) an engagement means formed in the end of the adapter opposite the protrusion, said engagement means being adapted to engage with the piston end of a syringe plunger.
The piston engaging means of the adapter can be a spiral thread and the releasable engagement means can be a male thread. The penetration means of the syringe can be releasably engaged with the end of the barrel means by means of an adapter, and the adapter means can be adapted to engage with the engaging means at the end of the plunger means proximate to the penetration means by rotating the plunger means. The adapter means can be releasably connected to the end of the barrel means by a female-male thread combination, and the means of the adapter means adapted to engage the engaging means of the plunger means can be a spiral thread combination with locking means.
The penetration means of the syringe can be a needle which is fitted with a Luer lock, the Luer lack being engaged with the adapter means. The needle-Luer lock combination and the adapter can be disengaged from the end of the barrel means by latch means which engages with the adapter when the plunger means is pushed to the needle end of the barrel and rotated to minimally withdraw and activate the engagement means.
The adapter can protrude partially from the penetration means end of the hollow barrel means and can have a thread direction which is the same as or opposite to the thread direction of the barrel means engaging the penetration means. The adapter can be designed to protrude partially from the penetration end of a syringe barrel.
In a further embodiment of the syringe the plunger is hollow and is a circular cylinder in cross section with a fastening means such as threads at the finger press end of the plunger. The plunger additionally includes a narrowed weakened break point whereby the hollow cylindrical portion of the plunger upon being withdrawn from the barrel may be broken away and fastened to the opposite end of the barrel whether or not the needle assembly has been withdrawn into the interior. Such construction allows for redundant manners of sheathing the needle assembly through the use of a needle guard or the cylindrical portion of the plunger. Both include threaded ends of the same size for attachment to the barrel and are relatively larger and more safely used than prior devices. Some additional features improve syringe function, for example, by enhancing the readability of calibration markings and thus improving the accuracy of the syringe.
In a still further embodiment of the invention, the needle guard and the hollow cylindrical portion of the plunger are the same element That is to say, the circular cylinder portion of the plunger includes at a narrowed intermediate point a reusable connection means in lieu of a break point. Such construction allows this portion of the plunger to be disconnected from the needle end portion of the plunger and used as a needle guard. Subsequently, this portion may be removed from the end of the barrel and reconnected to the needle end portion of the plunger. Moreover, such construction allows the interior of the syringe body to be sealed at both ends when the needle end portion of the plunger is withdrawn and the hollow cylindrical portion is in place on the barrel as a needle guard.
Additional features found in the further exemplary embodiments are the use of colored material for the plunger, which due to its close proximity to the inner surface of the barrel provides a less distorted or clearer background for viewing the barrel calibration markings. Still further, the inclusion of a radially linear surface on the interior far end of the plunger bung, as well as using bung material of the same color as the plunger, presents a single flat interface which dramatically improves the visualization of the calibration markings and the alignment of the end of the plunger with such markings. More accurate filling and delivery of contents is then possible.
Still further beneficial features of the disclosed exemplary embodiments include the use of annular ridges on the interior of the barrel and/or on the exterior of the plunger whereby the sealing ridges in combination with a needle guard attached to the opposite end of the syringe maintains sterile conditions in the syringe interior prior to use and after use seals bacteria or other material within the body of the syringe.
Additional features to be found in the exemplary embodiments include a cup-like annular lip or resilient pronged projections on the plunger adjacent the portion at the break point which are used in combination with the interior ridges of the barrel at the finger press end to deter the needle assembly from being completely withdrawn from the interior of the barrel means. Such elements also retain the needle assembly at the finger press end of the barrel. As an additional feature of the exemplary embodiments, the needle assembly includes an adapter-plunger connection which is designed to allow unidirectional torque only so as to prevent re-attachment of the adapter to the barrel means without the use of a special tool. Thus, subsequent use of the needle once the adapter and barrel have separated is prevented in the absence of special tools or extraordinary measures.
A further feature of the present invention resides in the provision of a venting structure in the adapter for venting air from the interior of the barrel once the barrel has been substantially filled with fluid to be injected and prior to injection. As well know, it is important that air be expelled entirely from the barrel so that air may not be injected with the fluid. In certain embodiments hereof, the hub or adapter, which releasably secures the needle to the distal end of the barrel and is adapted to be withdrawn with the needle from the distal end of the barrel into the interior of the barrel, has a connective structure which enables the plunger to grasp the adapter and withdraw the adapter and needle into the interior of the barrel. This connective structure protrudes toward the interior of the barrel, forming an annular space between it and the side walls of the barrel at the barrel""s distal end. When the axially extending fluid passage passes entirely through the adapter opening into the interior of the barrel at a location spaced from the distal end of the barrel, there is the danger that air can be trapped in such annular space notwithstanding movement of the plunger toward the distal end to vent the air. That is, the fluid in the barrel may occlude the central passage, and prevent the air trapped in the annular space from venting.
Therefore, in accordance with another aspect of the present invention"" the adapter is provided with one or more vent passages which open into the annular space at the most superior portion of the hollow barrel when the syringe is oriented substantially vertically with the needle uppermost. Consequently, after the fluid has been withdrawn into the interior of the barrel and the syringe oriented vertically needle end up, air is expelled through the vent passage into the central passage by moving the plunger toward the distal end of the barrel. The central passage may extend wholly through the adapter whereby the vent passage forms one or more branch passages of the central passage. Alternatively, the central passage may terminate within the adapter with more vent passages serving not only as air vents but passages for flowing the fluid through the needle during injection. To ensure that the vent passage(s) opens at the superior position in the interior of the barrel, the face of the radially enlarged portion of the adapter facing oppositely of the distal end of the barrel may be tapered radially inwardly toward the distal end of the barrel. Additionally, radial grooves may extend in the tapered adapter face and constitute continuations of the vent passages. Further, one or more annular grooves may be disposed in the tapered adapter face in communication with the radial grooves and vent passages, all to ensure venting of air from the syringe prior to use.
A further desirable feature of a syringe is that it may be packaged and sterilized in bulk and not necessarily in individual packages. However, this leaves open the possibility of tampering or inadvertent disruption of seals and contamination. It is important, therefore, that the syringe hereof embody tamperproof features. To that end, in one embodiment hereof, tamperproofing can be accomplished by applying a strip of paper tape having adhesive along one side along the side of the syringe covering both the junctures of the needle guard and body of the syringe and the proximal end of the barrel and plunger. Thus, if the tape has been broken or is twisted or otherwise removed from the syringe, it would be evident that the seals at the opposite ends of the syringe have possibly been disrupted. Similarly, in another embodiment hereof, a tight shrink-wrap of plastic material may be provided about these junctures. Again, removal to of the shrink-wrapped plastic material or a twisting or severing thereof would indicate a possible disruption of or tampering with the seals. In a further form of the invention, the syringe may be dipped into a plastic material in liquid form whereby a thin-film coating is applied to and solidified about the entire outer surface of the syringe, including the needle guard and projecting portion of the plunger. Consequently, sterility may be maintained, provided the thin-film plastic coating is not broken, while at the same time, disruption of or tampering with the seals at the aforementioned junctures is readily evident. The tamperproof seals may also be provided with sterilizing radiation sensitive material to evidence that the syringe has been sterilized and that the syringe remains sealed.
In a preferred embodiment according to the present invention, there is provided a syringe comprising (a) a hollow, axially elongated barrel, (b) an adapter carried by the barrel adjacent a distal end thereof and removable therefrom in response to rotation relative to the barrel, the adapter carrying a needle and providing fluid communication with the interior of the hollow barrel, (c) a plunger axially movable in the barrel between first and second positions relative to the barrel, (d) adapter engagement structure disposed at the distal end of the plunger and engageable with a mating connection engagement structure on the adapter, the structures having respective drive and connective engagement surfaces, the drive surfaces being engageable with one another when the plunger lies in the first position relative to the barrel and jointly movable to enable rotation of the adapter relative to the barrel in response to relative rotation of the plunger and barrel to cause the adapter to part from the distal end of the barrel, the connective surfaces being engageable with one another to connect the plunger and adapter one with the other and enable the adapter, when parted from the end of the barrel in response to joint rotation of the adapter and the plunger relative to the barrel, to be withdrawn with the needle into the interior of the barrel in response to joint axial movement of the plunger and the adapter in a direction away from the distal end of the barrel and (e) a cap carried by the barrel and movable between a position closing the distal end of the barrel and a position avoiding interference with the distal end of the barrel.